It is known to provide a vehicle seat with an inertia seat back latch arrangement for blocking forward tilting movement of a vehicle seat back under vehicle induced inertia forces. Reference may be had to Williams U.S. Pat. No. 2,732,003, Semar U.S. Pat. No. 2,737,229 and Leslie U.S. Pat. No. 2,873,794 for examples of such arrangements.
It is also known to provide an inertia seat back latch arrangement wherein the inertia latch member has a locking abutment gravity located in the path of a striker for inertia actuated engagement therewith but permitting relative movement between the latch member and the striker during normal movement of the seat back. Boschen U.S. Pat. No. 3,549,202 shows such an arrangement. It is also known to provide such an arrangement wherein the inertia actuated latch member is engageable with either of two shoulders of the striker under vehicle induced inertia forces. Arlauskas et al. U.S. Pat. No. 3,972,564 shows such an arrangement.
The arrangement of this invention is primarily intended for use with folding or displaceable rear seats of multipurpose vehicles. In such vehicles, the cargo to the rear of the seat may displace the tilting seat back of the seat from its upright position to one of a plurality of intermediate or partially tilted positions during normal usage of the vehicle. The invention provides a hinge and latch arrangement for mounting the seat back on the vehicle and holding the seat back against inertia actuated movement when the seat back is in its upright position and in each of a plurality of intermediate or partially tilted positions.
In a preferred embodiment, the arrangement includes a pair of pivotally interconnected hinge members, one being mounted on the vehicle and the other being mounted to the seat back to mount the seat back on the vehicle for movement: to an upright position; to a fully tilted generally horizontal position; and to a plurality of intermediate or partially tilted positions. An inertia actuated pawl is pivotally supported on the vehicle mounted hinge member for engagement with each of a plurality of teeth arranged radially about the pivot of the seat back hinge member and spaced circumferentially of each other. One tooth corresponds to the upright position of the seat back and the other teeth each correspond to a respective intermediate tilted position of the seat back.
When the seat back is in the upright position, the seat back hinge member engages a plastic coated abutment portion of the pawl to positively hold the pawl against movement and position the tooth of the pawl immediately adjacent to and directly in the path of one tooth of the seat back hinge member for instantaneous engagement therewith to block any movement of the seat back to a tilted position under vehicle induced inertia forces. When the seat back is in an intermediate tilted position, the seat back hinge member is disengaged from the pawl and the abutment portion of the pawl is gravity held against the vehicle mounted hinge member to locate the pawl tooth immediately adjacent to and out of the rotative path of movement of the other teeth of the seat back hinge member for movement into engagement with one of such other teeth under vehicle induced inertia forces.
Thus, in the arrangement of this invention, the pawl is positively held against inertia actuated movement and located in the path of one of a plurality of teeth when the seat back is in upright position to lock the seat back against inertia movement, and is gravity located for inertia actuated movement into the rotative path of others of the teeth when the seat back is in an intermediate tilted position to lock the seat back against further tilting movement. Thus, seat back inertia forces control the locking of the pawl when the seat back is in the upright position and pawl inertia forces control the locking of the pawl when the seat back is in an intermediate tilted position. The plastic coated abutment portion of the pawl and the seat back hinge member cooperatively provide a pawl anti-rattle feature when the seat back is in the upright position and the abutment portion and the vehicle mounted hinge member likewise provide the same feature when the seat back is in a partially tilted position.
In the interest of space economy, the vehicle mounted hinge member is of generally channel shape and the seat back hinge member is mounted between the side walls of the vehicle mounted hinge member. The teeth on the seat back hinge member are arranged radially and circumferentially about the pivot of the seat back hinge member and extend generally toward the base of the vehicle mounted hinge member. The pawl is also mounted between the side walls of the vehicle mounted hinge member and straddled by an edge of a cut out of the seat back hinge member. The seat back hinge member engages an integral rib of the plastic coated abutment portion of the pawl when the seat back is in the upright position, and such abutment portion gravity engages the base of the vehicle mounted hinge member when the seat back is in an intermediate tilted position. Further, a seat belt buckle support arm is coaxially mounted with the seat back hinge member and cooperating means between the support arm and the seat back hinge member moves the support arm and buckle to a stored position when the seat back is tilted and to an upright position when the seat back is in the upright position so that the buckle is always properly stored or located for use by a passenger in accordance with the position of the seat back.
The primary feature of this invention is that it provides a seat back hinge and latch arrangement having an inertia actuated rotatable pawl which is positively held against inertia actuated rotation and located for instantaneous engagement with a tilting seat back support member to block inertia movement of the seat back when the seat back is in a normal upright position and which is freed for inertia actuated rotation into engagement with such support member to block inertia movement of the seat back when the seat back is in one of a number of intermediate or partially tilted positions. Another feature is that the seat back support member includes a series of circumferentially spaced radially extending teeth arranged about the pivot axis of the support member on a vehicle mounted hinge member, with one of the teeth corresponding to the upright position of the seat back and being instantaneously engageable with the pawl upon inertia actuated movement of the seat back when the seat back is in the upright position, and the other teeth each respectively corresponding to one of the partially tilted positions of the seat back and being engageable by the pawl upon inertia actuated movement of the pawl when the seat back is in a corresponding partially tilted position. A further feature is that the seat back support member engages a plastic coated abutment portion of the pawl to noiselessly positively locate the pawl in the path of the one tooth when the seat back is in the upright position, and the abutment portion of the pawl engages the vehicle mounted hinge member under gravity bias to noiselessly locate the pawl adjacent the rotative path of the other teeth when the seat back is in one of the partially tilted positions. Yet another feature is that the vehicle mounted hinge member is of channel shape and the seat back support member and pawl are mounted between the walls of the vehicle mounted hinge member for space economy. Yet a further feature is that the vehicle mounted hinge member also supports a seat belt buckle support member coaxially with the seat back support member. Still another feature is that cooperating means between the seat back support member and the buckle support member locate the buckle in stored or in use position when the seat back is respectively in the tilted or upright position.